决策树是在已知各种情况发生概率的基础上，通过构成决策树来求取净现值的期望值大于等于零的概率，评价项目风险，判断其可行性的决策分析方法。代码通过汽车性能案例分别建立决策树和回归树进行预测。-Decision tree is based on the known probability of occurrence of various situations, through the decision tree to obtain the expected value of net present v